Study On Prediction Method Of Asphalt Content Of OGFC-13 Asphalt Mixture

In hot and rainy areas,OGFC asphalt mixture pavement has the characteristics of drainage,noise reduction,high temperature stability,no fog and high skid resistance etc.due to its large porosity and high content of coarse aggregate,and is more widely used in the road engineering currently.When the content of asphalt is inadequate,the asphalt cannot completely coat the aggregate or the formed oil film is too thin,easily causing the road to have poor water stability,loose structure,fatigue failure and other problems.When the content of asphalt is too high,the asphalt oil film is too thick,so that the road surface is more likely to appear rutting,bleeding,wrap and other distresses under the action of load.Therefore,precisely using the asphalt content is rather crucial for this type of asphalt mixture.This paper mainly deduced the asphalt content estimation formula of OGFC-13 asphalt mixture.The current OGFC asphalt mixture estimation formula determines the initial asphalt content merely through the specific surface area of aggregate and the thickness of oil film.However,the factors taken into account in this method are insufficient,so that the fluctuation of the estimated asphalt content in the initial test is very large in the case of little difference in gradation,lacking guiding significance for practical projects.The OGFC-13 asphalt mixture was selected as the research object and the apparent specific gravity(X1),bulk specific gravity(X2),specific surface area(X3)and the porosity(X4)were selected as the influencing factors of asphalt content,and the influence of these four factors on asphalt content was analyzed by using the existing data.Since both KMO test and Bartlett test were consistent,factorial analysis was conducted on the data and multiple regression analysis was conducted after reintegration.Then,according to the results of factorial analysis and multiple regression analysis,the formula P=3.945+(85.7Xi+83.8X2+48.9X3-20.7X4)×10-2 of the estimated asphalt content of OGFC-13 asphalt mixture was deduced.Finally,the optimal gradation was selected and the estimated asphalt content under this gradation was 4.6%,which turned out to be within the reasonable range of 4.1%～4.9%through Marshall test,Kentucky Fort flying test and leakage test.At the same time,high temperature stability,water stability,skid resistance and water permeability and other road performance tests were conducted.Based on the rationality verification and road performance test results,it is proved that the formula is scientific and feasible,and can provide reference for practical projects.Kentucky Fort flying.